Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Mol Sci ; 24(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36982686

RESUMO

The study of planar energy storage devices, characterized by low-cost, high capacity, and satisfactory flexibility, is becoming a valuable research hotspot. Graphene, monolayer sp2 hybrid carbon atoms with a large surface area, always acts as its active component, yet there is a tension between its high conductivity and ease of implementation. Although the difficult-to-assemble graphene can easily achieve planar assemblies in its highly oxidized form (GO), the undesirable conductivity, even after proper reduction, still restricts its further applications. Here, a facile "Top-down" method has been proposed to prepare the graphene planar electrode via in situ electro-exfoliation of graphite supported on a piece of laser-cutting patterned scotch tape. Detailed characterizations have been performed to study its physiochemical property evolution during electro-exfoliation. The obtained flexible graphene planar electrodes show decent energy storage performance, e.g., 40.8 mF cm-2 at a current density of 0.5 mA cm-2 and an 81% capacity retention at a current density of 8 mA cm-2 for the optimized sample G-240. Their high conductivity also makes it possible to couple them with other redox-active materials through electrodeposition to improve their performance, e.g., ferrocene-functionalized mesoporous silica film (Fc-MS), MnO2, and polyaniline (PANI). The highest capacity was achieved with the PANI functionalized sample, which achieved a 22-fold capacity increase. In a word, the versatility, practicality, and adaptability of the protocol to prepare the planar graphene electrode proposed in this work make it a potential candidate to meet the continuously growing energy storage demands.


Assuntos
Grafite , Grafite/química , Óxidos/química , Compostos de Manganês/química , Dióxido de Silício , Eletrodos
2.
Foods ; 11(11)2022 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-35681280

RESUMO

Tieguanyin (TGY) is one kind of oolong tea that is widely appreciated for its aroma and taste. To study the difference of volatile compounds among different types of TGY and other oolong teas, solid-phase microextraction−gas chromatography−mass spectrometry and chemometrics analysis were conducted in this experiment. Based on variable importance in projection > 1 and aroma character impact > 1, the contents of heptanal (1.60−2.79 µg/L), (E,E)-2,4-heptadienal (34.15−70.68 µg/L), (E)-2-octenal (1.57−2.94 µg/L), indole (48.44−122.21 µg/L), and (E)-nerolidol (32.64−96.63 µg/L) in TGY were higher than in other varieties. With the increase in tea fermentation, the total content of volatile compounds decreased slightly, mainly losing floral compounds. Heavily fermented tea contained a higher content of monoterpenoids, whereas low-fermentation tea contained higher contents of sesquiterpenes and indole, which could well distinguish the degree of TGY fermentation. Besides, the volatiles analysis of different grades of TGY showed that the special-grade tea contained more aroma compounds, mainly alcohols (28%). (E,E)-2,4-Heptadienal, (E)-2-octenal, benzeneacetaldehyde, and (E)-nerolidol were the key volatile compounds to distinguish different grades of TGY. The results obtained in this study could help enrich the theoretical basis of aroma substances in TGY.

3.
ACS Appl Mater Interfaces ; 12(21): 24262-24270, 2020 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-32366093

RESUMO

Organic-inorganic hybrid membranes, made of a high density of redox active moieties covalently bonded to the internal surfaces of vertically aligned mesoporous silica thin films, are relevant for applications in transparent energy storage devices. This is demonstrated here on the basis of functionalized transparent mesoporous silica thin films prepared on the indium-tin oxide electrode from the combination of an electrochemically induced self-assembly method (to generate azide-functionalized silica) and a copper-catalyzed azide-alkyne click reaction (to derivatize the material with electroactive groups). The very small thickness (105 nm) and the uniformly distributed vertical mesochannels with ultranarrow diameter (2 nm) make the hybrid film a promising substrate that not only achieves a transparency of 82% but also provides large surface area to accommodate a high density of redox active species such as ferrocene. In such rigid and insulating porous membranes, the charge transfer reactions take place through a pure electron-hopping mechanism between adjacent redox sites, which are favored by the ordered and oriented mesostructure containing large amounts of uniformly distributed ferrocene functions in the mesochannels. Their performance results from both high charge transfer rates (electron hopping) and easy mass transport (fast diffusion of counter ions). The most effective system is the ferrocene-functionalized silica film prepared from 40% organosilane, which is able to deliver a capacity of 105 C cm-3 (1.10 mC cm-2) at a current density of 0.4 A cm-3 (with up to 48% capacity retention achieved at a charging time as short as 2.8 s). Such an electrode can be associated to an electrodeposited graphene anode in a solid-state battery-capacitor hybrid device, which can deliver 0.74 mC cm-2 at a potential scan rate of 20 mV s-1. The azide-functionalized mesoporous silica film is actually a versatile platform that can be functionalized with different redox molecules, as shown here for cobaltocenium moieties, which may broaden its application field.

4.
J Colloid Interface Sci ; 552: 604-612, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31170613

RESUMO

Capacitive deionization (CDI) has long been identified as a hopeful solution for adsorption of ions from saline water. Developing stable electrode materials is of great significance to the improvement of CDI performance. In this work, two kinds of boron-nitride-carbon (BCN and MBCN) materials were synthesized for capacitive deionization (CDI) application. The BCN featured with high specific surface area (1097.5 m2 g-1) and positive surface charges (Epzc of -0.445 V vs. Ag/AgCl) is a good anodic candidate in the CDI device. After configuring with activated carbon, the asymmetric CDI cell exhibits excellent salt adsorption capacity of 17.46 mg g-1 at supplied voltage of 1.4 V when the feeding NaCl concentration is 300 mg L-1 and robust cycle performance with 81.4% capacity retention after 50 cycles at supplied voltage of 1.0 V with initial salt concentration of 500 mg L-1. Overall, in contrast to that of MBCN and carbon materials, the BCN nanosheets demonstrate a high removal capacity and superior cycling stability even at low salt concentration. The stable and positively charged BCN should be a good choice for next generation of high performance CDI electrode materials.

5.
Med Sci Monit ; 24: 8115-8124, 2018 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-30419569

RESUMO

BACKGROUND The aim of this study was to retrospectively analyze the incidence of complications of intracranial complex aneurysms embolization by stent-assisted coils, and to investigate the causes of complications and corresponding treatment methods. MATERIAL AND METHODS A total of 71 patients with subarachnoid hemorrhage (SAH) underwent stent-assisted coil embolization from 2015 to 2018 were enrolled in this study. Among them, 59 cases were single aneurysm, 12 cases were multiple aneurysms (11 cases with 2 aneurysms and 1 case with 3 aneurysms), for a total of 84 aneurysms. All enrolled patients received stent angioplasty except for 1 case. RESULTS There were 62 aneurysms (73.81%) treated with complete tamponade, 21 aneurysms (25.00%) treated with near-total tamponade and 1 aneurysm (1.19%) treated with partial tamponade. All aneurysms were evaluated based on GOS (Glascow outcome scale): 55 cases had GOS of 5 scores, 12 cases had GOS of 4 scores, 3 cases had GOS of 3 scores, and 1 case had GOS of 1 score. There were 67 SAH patients with good prognosis (GOS of 4-5 scores). In our study, the incidence of complications was 12.7%. Three cases experienced acute thrombosis, 2 cases experienced aneurysm rupture during embolization, and 1 case experienced postoperative focal ischemic changes with mild neurological deficits. CONCLUSIONS Stent-assisted coil embolization is safe, effective, and feasible for the treatment of intracranial ruptured aneurysms. Patients had a favorable outcome of as high as 94.4%. However, clinical skills should be improved to reduce the occurrence of complications. Prompt and timely treatment for complications of intracranial ruptured aneurysm is also of great significance.


Assuntos
Aneurisma Roto/complicações , Aneurisma Roto/terapia , Embolização Terapêutica/métodos , Aneurisma Intracraniano/complicações , Aneurisma Intracraniano/terapia , Stents , Adulto , Idoso , Oclusão com Balão/métodos , Prótese Vascular , Embolização Terapêutica/instrumentação , Feminino , Humanos , Embolia Intracraniana/terapia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Hemorragia Subaracnóidea/terapia , Resultado do Tratamento
6.
J Biomech Eng ; 140(3)2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29238806

RESUMO

Vertical jump height is widely used for assessing motor development, functional ability, and motor capacity. Traditional methods for estimating vertical jump height rely on force plates or optical marker-based motion capture systems limiting assessment to people with access to specialized laboratories. Current wearable designs need to be attached to the skin or strapped to an appendage which can potentially be uncomfortable and inconvenient to use. This paper presents a novel algorithm for estimating vertical jump height based on foot-worn inertial sensors. Twenty healthy subjects performed countermovement jumping trials and maximum jump height was determined via inertial sensors located above the toe and under the heel and was compared with the gold standard maximum jump height estimation via optical marker-based motion capture. Average vertical jump height estimation errors from inertial sensing at the toe and heel were -2.2±2.1 cm and -0.4±3.8 cm, respectively. Vertical jump height estimation with the presented algorithm via inertial sensing showed excellent reliability at the toe (ICC(2,1)=0.98) and heel (ICC(2,1)=0.97). There was no significant bias in the inertial sensing at the toe, but proportional bias (b=1.22) and fixed bias (a=-10.23cm) were detected in inertial sensing at the heel. These results indicate that the presented algorithm could be applied to foot-worn inertial sensors to estimate maximum jump height enabling assessment outside of traditional laboratory settings, and to avoid bias errors, the toe may be a more suitable location for inertial sensor placement than the heel.


Assuntos
Aceleração , Algoritmos , , Fenômenos Mecânicos , Movimento , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino
7.
J Biomech ; 61: 193-198, 2017 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-28780187

RESUMO

The foot progression angle is an important measurement related to knee loading, pain, and function for individuals with knee osteoarthritis, however current measurement methods require camera-based motion capture or floor-embedded force plates confining foot progression angle assessment to facilities with specialized equipment. This paper presents the validation of a customized smart shoe for estimating foot progression angle during walking. The smart shoe is composed of an electronic module with inertial and magnetometer sensing inserted into the sole of a standard walking shoe. The smart shoe charges wirelessly, and up to 160h of continuous data (sampled at 100Hz) can be stored locally on the shoe. For validation testing, fourteen healthy subjects were recruited and performed treadmill walking trials with small, medium, and large toe-in (internal foot rotation), small, medium, and large toe-out (external foot rotation) and normal foot progression angle at self-selected walking speeds. Foot progression angle calculations from the smart shoe were compared with measurements from a standard motion capture system. In general, foot progression angle values from the smart shoe closely followed motion capture values for all walking conditions with an overall average error of 0.1±1.9deg and an overall average absolute error of 1.7±1.0deg. There were no significant differences in foot progression angle accuracy across the seven different walking gait patterns. The presented smart shoe could potentially be used for knee osteoarthritis or other clinical applications requiring foot progression angle assessment in community settings or in clinics without specialized motion capture equipment.


Assuntos
Marcha , Osteoartrite do Joelho/diagnóstico , Sapatos , Adulto , Fenômenos Biomecânicos , Pé/fisiopatologia , Humanos , Articulação do Joelho/fisiopatologia , Masculino , Osteoartrite do Joelho/fisiopatologia , Adulto Jovem
8.
Water Res ; 93: 30-37, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26878480

RESUMO

The potential of zero charge (Epzc) of electrodes can greatly influence the salt removal capacity, charge efficiency and cyclic stability of capacitive deionization (CDI). Thus optimizing the Epzc of CDI electrodes is of great importance. A simple strategy to negatively shift the Epzc of CDI electrodes by modifying commercial activated carbon with quaternized poly (4-vinylpyridine) (AC-QPVP) is reported in this work. The Epzc of the prepared AC-QPVP composite electrode is as negative as -0.745 V vs. Ag/AgCl. Benefiting from the optimized Epzc of electrodes, the asymmetric CDI cell which consists of the AC-QPVP electrode and a nitric acid treated activated carbon (AC-HNO3) electrode exhibits excellent CDI performance. For inverted CDI, the working potential window of the asymmetric CDI cell can reach 1.4 V, and its salt removal capacity can be as high as 9.6 mg/g. For extended voltage CDI, the salt removal capacity of the asymmetric CDI cell at 1.2/-1.2 V is 20.6 mg/g, which is comparable to that of membrane CDI using pristine activated carbon as the electrodes (19.5 mg/g). The present work provides a simple method to prepare highly positively charged CDI electrodes and may pave the way for the development of high-performance CDI cells.


Assuntos
Carbono/química , Técnicas Eletroquímicas/instrumentação , Cloreto de Sódio/isolamento & purificação , Purificação da Água/instrumentação , Adsorção , Carvão Vegetal/química , Capacitância Elétrica , Técnicas Eletroquímicas/métodos , Eletrodos , Desenho de Equipamento , Ácido Nítrico/química , Polivinil/química , Reprodutibilidade dos Testes , Salinidade , Cloreto de Sódio/química , Propriedades de Superfície , Purificação da Água/métodos
9.
Cancer Lett ; 290(2): 248-54, 2010 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-19853373

RESUMO

Accumulating evidences have demonstrated that mTOR pathway has a central role not only in cell growth but also in invasion and metastasis of cancers. Here we reported that rapamycin or cisplatin alone inhibited significantly the tumor growth and their combination had the strongest anticancer effect on transplantable tumor growth of human ESCC cell line EC9706 in nude mice. Furthermore, western blots, RT-PCR and TUNEL assay revealed that rapamycin specifically blocked mTOR pathway and induced apoptosis of ESCC cells in vivo. These findings indicate a rationale for using mTOR inhibitors as a mechanism-based therapeutic approach to patients with ESCC.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Escamosas/metabolismo , Cisplatino/farmacologia , Neoplasias Esofágicas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Sirolimo/farmacologia , Idoso , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Carcinoma de Células Escamosas/patologia , Proliferação de Células/efeitos dos fármacos , Neoplasias Esofágicas/patologia , Feminino , Humanos , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Peptídeos e Proteínas de Sinalização Intracelular/efeitos dos fármacos , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Neoplasias Experimentais/tratamento farmacológico , Proteínas Serina-Treonina Quinases/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Serina-Treonina Quinases TOR , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 15(4): 839-44, 2007 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-17708815

RESUMO

FMS-like tyrosine kinase 3 (FLT3) is a receptor of tyrosine kinase that is constitutively activated in most of acute myeloid leukemia patients and seems to give an adverse prognosis. In order to explore the silencing effect of FLT3 targeted short hairpin RNA (FLT3-shRNA) on acute leukaemia cell line THP-1, three FLT3-shRNAs (shRNA1, shRNA2, shRNA3) were designed and synthesized by transcription system in vitro and then transfected into THP-1 cells. FLT3 mRNA was analyzed by semi-quantitative RT-PCR, FLT3 protein was detected by Flow cytometry and immunofluorescence. The results indicated that FLT3 expression was downregulated by shRNA1 and shRNA3, and shRNA1 showed stronger inhibitory effect. At 48 hours following transfection, the inhibitory rate of 25 nmol/L shRNA1 was 72.95 +/- 2.07%, lasting 72 hours. The 5 nmol/L and more concentration of FLT3 shRNA1 could downregulate FLT3 mRNA level, which displayed a quantity-effect relation; the inhibitory rate of 15 nmol/L shRNA1 was 67.53 +/- 0.66%. FLT3 protein was located on THP-1 cell membrance, its expression was downregulated obviously by shRNA1, at 72 hours following transfection the inhibitory rate of shRNA1 was 79.67 +/- 0.66%. shRNA1 showed the best inhibitory effect on FLT3 protein, the optimal time of which was 72 hours with an inhibitory rate of 79.67%. It is concluded that FLT3-shRNA1 shows a desireable FLT3-targeted inhibitory effect, which can be used for further investigation of FLT3 mechanism or FLT3 targeting treatment.


Assuntos
Leucemia Mieloide Aguda/genética , RNA Interferente Pequeno/genética , Transcrição Gênica , Tirosina Quinase 3 Semelhante a fms/genética , Humanos , Leucemia Mieloide Aguda/metabolismo , Interferência de RNA , RNA Mensageiro/genética , Células Tumorais Cultivadas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...